I had my truck up on stands last week to rotate my tires and noticed that my rear wheels move in and out about a 1/4" or so. Pushing them in and out caused a clunking sound. I checked to see if there was any movement by pushing and pulling at 6 and 12 o'clock and at 3 and 9 o'clock. Everything seems fine that way. To me this doesn't seem normal and lately I have felt that the truck seems to "float" on the highway. It is harder to control escpecially when changing lanes. The steering itself seems tight. Any ideas?

The 8.8 rear end is a semi-floating axle. The axleshafts are held in place by C-clips inside the differential. Some movement (and I wouldn't say 1/4" is excessive) is to be expected.

The same in mine. When doing brakes I noticed both rear axle shafts move like 1/4" in and out. Mechanic says it's OK, don't worry about it since there isn't any radial play. He also says in case of radial play I would have seen slight seal leaks. Makes sense.

ok, that makes me feel better. Then my front end must be causing the truck to "float". I guess it is most likely my hubs since I am having some problems with 4x4 and the front end is making a whirring or chuffing sound.